Electroplating of the cut edges of sheet metal panels

ABSTRACT

Apparatus for electroplating the cut edges of sheet metal panels including a container for the electrolyte and a lid mounted air tight on the container. A stack of the panels are supported so that the edge portions of at least one side of the panels are aligned. At least one anode is mounted in the container and each sheet metal panel is directly electrically contacted with the cathode of a direct current source, whereby the edge portions of the panels may be electroplated simultaneously.

.ilnite ttes atet 3 72 Mar. 4, 197sv Becker ELECTROPLATING OF THE CUT EDGES 2/1954 Robinson.............................. OF SHEET METAL PANELS FOREIGN P TENTS OR APPLICATIONS 5 H 4 0 2 .m a H r B t. a e. r. G 8 5 9 H 2 0 6 w 0 9 7 [76] Inventor: Otto Alfred Becker, 59 Robert Koch Strasse, T-66OO 6 Saarbrucken, Germany [22] Filed: Dec. 2, 1971 Primary Examiner-John H. Mack pp NO-z 204,385 7 Assistant Examiner-W. l. Solomon Attorney, Agent, or Firm-Erich M. H. Radde 835,116, June 20, 1969,

ABSTRACT abandoned.

Foreign Application Priority Data June 20. 1968 Germany...

1771 45 metal panels including a container for the electrolyte 1771933 and a lid mounted air tight on the container. A stack 1803474 of the panels are supported so that the edge portions ed. At least Aug. ll I968 Germany..... Oct. l7 i968 of at least one side of the panels are align t wmm m fih hum mcd e d r-h ameD. rn o own .m ,C t B ml m l Ow e C.lm BH nmflna ndmm ym M196 tC n ne a u. hp wdn n .ml f e mO M8 n l l a 0.w m tin e rO n H omcpn mmw 7 /57 1 2 NIB 7, 5 C. v 2 4 m4 lv G 4 H/ 27 7/2922 4H m. 04 u 20 H um m v Tn .c r u a n U& L ."f C U o M 5 m .w l 11] 2 00 5 55 References Cited UNITED STATES PATENTS 13 Claims, 18 Drawing Figures PATENTED-KAR 4197s 3869,1372

' SHEET UlUF 13 Fig.1

PAIENIEU W5 I 3,869,372

SHEET can? 13 Fig.2

PATENIEDHAR 41915 3,869.372

' SHEET U30F13 PATENTEUKAR 4% v 3.869.372

sum user 13 7 PATENTEUNAR SHEET UBUF 13 PATENTED W5 3,869,372

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PATENTEU 41975 SHEET 120F 13 I 1 ELECTROIPLATING OF THE CUT EDGES OF SHEET METAL PANELS This is a division of application Ser. No. 835,l l6, filed June 20, 1969 and now abandoned.

For treatment, sheet metal panels are firstly cut to size, then shaped'by bending, pressing, or the like to the form desired, and connected to other compounds. The cut edges generally lie at inaccessible places and are protected with difficulty from corrosion. When treating sheet metal panels previously coated with lacquer, synthetic substances or synthetic foils or other rust protective materials, unprotected cut edges are formed when cutting these panels to shape. When using such sheet metal panels in the construction of our bodies, boats, wagons, facades of buildings, wall units, kitchen or bathroom furniture this lack of protection gives rise to corrosion. It is known, though, to electroplate individual places of work pieces by means of manually operated tools, wherein an electrolyte is applied to these places by means of sponges or pieces of felt. This method is, however, uneconomic for the electroplating of the cut edges of sheet metal panels.

The present invention has the object of providing an economic method for the electroplating ofthe cut edges of sheet metal panels,'which is suitable for mass production.

BRIEF SUMMARY OFTHE INVENTION According to the invention, for the electroplating of the cut edges of sheet metal panels placed one on top of the others in a'pile at least one face to be electroplated of the pile is brought into contact with the electaneously. Assuming a thickness of 1 mm of'each sheet metal panel I000 panels form a pile of 1 m height which may beelectroplated in the usual period of about 25 minutes. i

According to a first embodiment, one wall of an electrolyte container is made of an absorbent material such as panels of felt, sponge or foam material, and one face ofthe pile is pressed against it. When two such electrolyte containers are pressed on opposite faces of the I pile, two faces of the pile'may be electroplated simultaneously. By the additional provision of strips of absorbent material to said wall the edges of sheet metal panels having punched cut-outs may be electroplated.

According to asecond embodiment one wall of the electrolyte container is provided with an opening; part of the pile of sheet metal panels is introduced through said opening; said opening is sealed; the container is filled with the electrolyte; the electrolyte is sucked off and the pile of sheet metal panels is taken out. Thus curved and serrated edges ofsheet metal panels may be electroplated. The sealing of the opening may be effected by movable wall portions with sealing means or by an annular sleeve with presser means.

According to a third embodiment, the pile of sheet metal panels is completely inserted into an empty electrolyte container, then a casing with contact brushes is pressed in a liquid-tight manner on the pile, the container is sealed and electroplating is carried out after filling the container with electrolyte. During the electroplating the casings with'the contact brushes may be moved along the pile so that all four faces of a be electroplated in a single operation.

An advantageous apparatus comprises a piling plate for the pile of sheet metal panels, a sealingframe resting on said piling plate, removable sidewalls of the container engaging in the sealing frame, and attachment pile may means which hold the frame for the side walls of the r BRIEF DESCRIPTION OF- SEVERAL VIEWS OF THE DRAWING Several embodiments are illustrated in the accompanying drawings by way of example, wherein:

FIG. 1 is a perspective view'of an electroplating apparatus for a pile of sheet metal panels cut to shape contacting an absorbent wall of an electrolyte con-.

tainer.

FIG. 2 is a sectional elevation on the line II-II of FIG. 1. l

FIG. 3 is a section on a larger scale of side upper corner, and

FIG. 4 of the left hand side upper corner.

FIG. 5 is a part sectional elevation of a-second embodiment with a pile of sheet metal panels partly inserted in an electroplating container. f

FIG. 6 is a partial front elevation thereof. with sealing walls. 7

FIG. 7 is a section on a larger scale ofa sealing wall.

FIG. 8 shows in section a modification with a sealing sleeve embracing the pile of sheet metal panels.

the right hand FIG. 9 is a front elevation to FIG. 8 with the pile of FIG. 13 is a partial longitudinal section of the said container.

FIG. 14 is a partial sectional plan view thereof show ing contact brushes.

FIG. 15 is a sectional elevation ofa modification hav- 5 ing a dismountable container.

FIG. 16 is a section on an enlarged scale of the mounting'and sealing of a wall thereof.

' FIG. 17 is partial longitudinal section of that container and FIG. 18 is a partial plan view in section thereof. DETAILED DESCRIPTION OF THE- INVENTION Referring to FIGS. 1 to 4, a trolley 16 carries an electrolyte container 1. The latter has a lid 1b, which rests on the frame of the container in an. air-tight manner by means of a rubber seal 2. The front wall la of the connetting 4 (-FIG. 2), then two panels 5 of absorbent material, a further wire netting 4 and a further absorbent 'panel 5 are inserted. These panels may consist of felt,

sponge or foam material, and may have varying degrees of permeability to liquid or may be composed of sepa- 3 rate horizontal strips, the permeability of which diminishes downwardly. The frame 3a is held by screws 3b on alongitudinal container wall, with a seal2a interposed. Electrolyte dripping off the wall 3 is collected in a trough I and is returned by a pipe line 11 to the top of the container, 1. l-n order to keep the electrolyte level 9 steady, the end of the pipe line 11 is provided with a fl'oat valve 12 (FIG. 4); a valve seat 12a thereof rests the cone of a float 12b which is guided by a stern 120 in a holder 11b. A further pipe line 15 leads to asuction plant, so that electrolyte is automatically sucked in,

when the level 9 drops. Anode metal sheets 18 are suspended by hooks 19 on horizontal conductor bars 20. These bars 20 rest on semicircular brackets 21.

The sheet metal panels cut to shape and to be electroplated are superimposed upon each other in a pile l7 and are held by a lower holder plate 31, an upper holder plate 32 and by abutment rods 34, which are pushed through the lateral projections of said holder plates. These lateral projections may be articulated pivotally on all edges ofthe holder plates, in order to make all'faces of the pile in turn accessible to electroplating. The sheet metal panels, which are preferably coated with synthetic material, lacquer or other insulating material, are connected to the cathode of a direct current source. For this purpose contact strips 30 are provided e.g., brushes of copper wire, which may be mounted in slots of the said projections ofjthe holder plates. For formation of intensive contacts they may be pressed on by springs or vibratory electromagnets.

The pile of sheet metal panels rests on a trolley and is held against the permeable wall 3 by means of hooks 26. For intensive contact with the cut edges small oscillations may be imparted by means of electromagnets energised by alternating current to the permeable wall which bears on rubber seals. If desired the electrolyte container may be movable to-and-fro on rails along said pile.

Preferably acidic electrolytes or such cyanide electrolytes are to be used which produce a 100% yield of current. When electrolytes are used wherein gaseous hydrogen is developed at the cathode, the surfaces of the lateral wall panels are preferably formedwith vertical corrugated troughs and ridges, so that the hydrogen gas can escape through the troughs. The frame 30, is to be moved so that all parts of the faces of the pipe'come into contact with the electrolyte.

The electroplating of the cut edges presupposes their previous cleansing from adhering particles derived, e.g., from their casings as'well as from oil. This cleansing may be effected by a device comprising cleansing brush bars movable in the longitudinal direction of the cut edges, which bars may at the same time spray water containing suitable chemicals against the face of the pile. These cleansing brush bars may be arranged at short intervals from each other and be actuated by a motor to perform reciprocating movements in unison. After electroplating, an-after-treatment may be performed, for example by the same device. Afurther chemical treatment may follow, e.g. chromium plating of'the cut edges, which were for example previously zinc-plated. The said device may be mounted on the upper holder plate 32 in the manner of a horizontal sprinkler, or from outside; collector troughs, if desired with pumps, are then provided.

Finally it is also possible to oxidize or anodize the cut edges e.g. ofaluminium sheetpanels with the aid of 4 said device, by reversing the connections of anode and cathode, i.e. by connecting the pile of aluminium sheet panels to the positive pole of a direct current source.

The cut edges may have punched recesses which may serve for'subsequentangularly turning up the margins of the panels. Such cut edges having re-entrant portions are simultaneously electroplated by means of vertical electroplating strips, 27, 28 the cross section of which is complementary to that of'the punched recesses of the panels, which strips are for example mounted on the frame 3a, by means of clamps. These strips carry absorbent material adjacent to said punched cut-outs and to the lateral wall panel 3, which material takes over the electrolyte from the lateral wall panel.

In a modification illustrated in FIG. 3 the electroplat-- ing strips 27 are adjustable by means of Z-shaped brackets 27a, and are mounted exchangeably on C- se ction rails 30 of the carrier frame by the aid of screws 27b, and clamping members 270. For large punched recesses the electroplating strips may contain anode rods 22 in their interior, which rods are surrounded by sievelike tubes 23. Thus the electrolyte may flow about the anoderods, and gases liberated on the anode may'rise along the anode.

In a second embodiment according to FIGS. 5 to 11 'a pile 17 of sheet metal panels lying on a trolley 25 is introduced partly into an electroplating container through an aperture in the front wall 1a thereof, whereafter the said opening is closed by movable wall portions 43, 44 which are sealed all round the pile of sheet metal panels in a liquid-tight manner. Then electrolyte is forced from a storage container mounted on a trolley 62a and closed by an air tight lid 64 into said electroplating container 1 through a pipe 61 with stopcock 61a by compressed air introduced through a pipe 63. The electroplating container 1 rests on a trolley 16 having'a collector trough 10. All round the'front wall 1a a frame 41 is arranged which is made of U-section bars. Into said U-sections open in front an endless hose 42 is inserted which hose can be inflated through a valve by compressed air and thus pressed on the movable wall portions. Theupper wall portion 43 and the lower wall portion 44 are guided at their backs by a framing 53 on the trolley and on the container, respectively, and at their fronts by vertical rails 48 as well as by horizontal rails 51,52 and ispressed on the pile I7 7 by a pressure cylinder 49 with piston rod 50, if desired with rails 54 interposed. These wall portions carry on their front edges directed towards the pile of sheet metal panels inflatable hoses 47 and sealing means e.g. rubber strips 44a (FIG. 6). On the underside of the pile of sheet'metal panels and above the frame 41 compound of U-sectio'ns an upwardly open U-section 45 with an inflatable hose 46 is arranged for sealing. Thereby the pile of sheet metal panels as well as the container can be sealed'relative to the walls. Anode metal sheets 18 are suspended in the container. Each sheet metal panel is connected to a-direct current circuit (not shown) whereby a pile of such panels may be electroplated simultaneously.

These wall portions may also be-enlargeable. In accordance with FIG. 7 the aperture of it U-section 66a is overlapped by a second U-section 66b. and in the. cavity thus formed a hose 68 is arranged which may be inflated through a port 70 with a valve (not shown). When being inflated, the hose forces the said two U- sections apart which are guided in each other. In FIG.

7 in the first U-section thereis arranged a second pair front wall 111 of the electroplating container, with a seal interposed.

In a modification according to the FIGS. 8 to.11 a rubber sleeve 101 is used for sealing the pile 17 of sheet metal panels, which panels rest on a trolley 25, relative to container 1a, which sleeve is clamped at its outer margin to the inside of the front wall 1a, and with its inner margin turned outwardly is applied all round the pile of sheet metal panels. For sealing, presser bars 105 with inserted rubber strips 106 bear on the inner margin thereof, which bars may be pressed on the pile of sheet metal panels by pressure cylinders 82 with piston rods 83. These pressure cylinders are mounted on a bracket 108 fixed to the electroplating container 1 and to the trolley 16. On the outside of the inner margin of the said sleeve and opposite the corners of the pile of sheet metal panels cables 110 are attached which are passed over rollers 110ato reels (not shown). By a pull on said cables the aperture of the resilient sleeve is enlargetl so that the pile of sheet metal panels may be pushed in. For perfect contact of said sleeve with the corners of the pile, presser corner pieces 107 and extensible bars 1050 may be provided, which are adaptable to the actual cross-section of the pile of sheet metal panels and may be pressed on the same by pressure cylinders 82 and piston rods 83.

In accordance with FIG. l0.these presser bars 105b may have a U-shaped cross section with box-profile flanges. In the aperture of the Usection an inflatable hose 106a and a further U-section bar 1056 are inserted. The faces ofthe bars 105b, 105a contacting said sleeve carry resilient strips 106.

In FIG. 11 extensible bars 105a are-provided at the upper face and underside ofthe pile of sheet metal panels forming horizontal seals, and presser bars 109 are arranged at the vertical faces of said pile, the length of which exceeds the maximum height of said pile and which, when being pressed on by pressure cylinder 82 and piston rods 83, at the same time push the horizontal presser bars towards each other. The pressureapplied by the pressure cylinders also compresses the pile of sheet metal panels in such a manner that any penetration of electrolyte between said sheet metal panels is prevented. The trolley 25 carrying said pile has legs; which are extensible, carry castors and are fixable by means of screws 250 (FIG. 8).

In a third embodiment the pile of sheet metal panels is inserted as a whole into the electrolyte container. The apparatus according to FIGS. 12 to 14 comprises likewise a storage container 62 with an air tight lid'64 and resting on a trolley 62a. vOn top a pipe 63for the application of suction or air pressure is arranged, and

on the bottom a pipe 61 with stopcock 61a leads to the electroplating container 1 which rests on a trolley 111. The front wall of the container has an opening, which can be closed in a liquid-tight manner by a lid 112 and screws.

When the electrolyte is sucked off and the lid is opened, the pile 17 of sheet metal panels is inserted on a support base 114. For this purpose, the sheet metal panels are placed on a bottom plate 121 e.g. wood, and are coveredon top by an identical top plate 121. In the container there is provided a U-shaped frame 122,- which straddles the pile of sheet metal panels which is pushed into it. This frame carries upper pressure cylinders 118 for compressing the pile. On the sides of the frame further pressure cylinders 118 are arranged for pressing the contact brushes 115 on the said pile (FIG.

13). Around the said contact brushes an electrically insulating casing 116is placed, which is sealed by rubber '4 strips 117 against said pile. The flexible backs of the said contact brushescontact a soft rubber mass 119 which fills the remainder of the cavity of said casing.

' Additionally, compressed air may be introduced through a port 120 controlled by a valve (not shown) arranged on top of said contact brush casing in order to prevent the entry of electrolyte. The said contact brushes may be oscillated by alternating current supplied to electromagnets (not shown). Opposite the faces to be electroplated of said pile, anode metal sheets 18 are suspended (FIG. 12)

In the embodiment according to the FIGS. 15 to 18 the electroplating container 1 is dismountable in order to avoid difficulties when inserting the heavy pile of sheet metal panels. On a trolley 111 a piling table 132 is arranged, on the carrier strips 114 of which firstly a lower cover plate 121, then the sheet metal panels cut to shape are placed in a pile 17 covered by one or more top plates 121. For the purpose of sealing, a presser frame 134 (FIG. 16) is placed on the piling plate around the said pile, which frame consists in a. U- section open inwardly and carries on it's underside a seal 2b. Into said presser'frame four side walls 131 of the container are inserted which form a frame open on top and bottom.'On their lower edge, Z-profile sections 135 are attached, which together with the sidewalls form a cavity opening downwardly for the accomodation ofa house 137. The frame formed by the side walls is held by attachment means e.g. by clamps 133, which are mounted pivotably on the piling plate. By inflating the hose through a port 138 controlled by a valve (not shown) the side walls are sealed against the pilings plate, and the electroplating container is ready for .being filled with electrolyte from the storage container 62 through the pipe 61 (FIG. 15). Anode metal sheets 18 are to be suspended in said container. For the supply of current to the edges of the sheet metal panels, contact brushes 115 are provided in the casings 116 (FIG. 17). These casings press the contact brushes against said pile through soft rubber layers 119 and are sealed by rubber strips 117 against said pile. being pressed on said pile by pressure cylinders 118. These pressure cylinders are arranged on vertical hollow sections 140 which are mounted slidably on top and botsheet'metal panels of any metal, coated with any layers e.g. lacquer, synthetic substances or metallic coatings 7 7 o'rplatings, may be electroplated. When'the pannels have electrically conductive coatings, the penetration of electrolyte between the sheet metal panels is to be prevented by the interposition of tapes self-adhesive on both sides or of protective foils between the margins of the panels.

I claim:

1. Apparatus for electroplating the cut edges of sheet metal panels comprising:

a. a container forthe electrolyte, a lid for the container, and means for retaining said lid air tight on said container;

b. means separate from said container for supporting a stack of said sheet metal panels and substantially aligning the edge portions of said panels on at-least one side thereof;

c. at least one anode mounted in said container;

d. means, for directly electrically contacting each sheet metal panel for connecting the same to the cathode of a direct current source, and

e. means for conducting current to said contacting means whereby said cut edges are electroplated.

2. The apparatus of'claim 1, wherein said stack supporting means comprises holder plates covering said stack and having lateral projections, and abutment rods and contact bars'mounted on said projections, said contact bars comprising said current conducting means.

3. The apparatus of claim 1 wherein said container has an absorbent wall composed of members of permeable material, wire grids supporting said permeable members, a frame attaching said absorbent wall zone to said container, and sealing means interposed between said absorbent wall zone and said container.

4. The apparatus of claim 3, further including strips of absorbent material clamped vto said frame and having cross sections complementary to recesses in said cut edges of said panels.v

5. The apparatus of claim 3, further including a suc-' tion pipe communicating with the interior of said container, a collection trough for electrolyte dripping off said absorbent wall, an electrolyte return pipe, and a float valve arranged above the electrolyte level in said container for controlling said return pipe.

6. The apparatus of claim 1 further including a second container separate from said first container for storing the electrolyte, a pipe having a stop valve connecting said second container to said first recited container, and a pipe connecting said storage container to suction for filling the same with electrolyte and to pressure for emptying the same. t 7. The apparatus of claim 6, wherein said stack is partly inserted into said first recited container. and further including horizontally and vertically slidable wall portions sealing said stack when so inserted into said first recited container, rails mounted on said first container guiding said slidable wall portions, inflatable hoses and sealing strips provided on the end of faces of said movable wall portions, pressure cylinders having piston rods mounted on said'flrst container and in operation pressing said wall portions on said stack, generally U-shaped frame sections arranged parallel to the edges of said wall portions, and inflatable hoses arranged in said sections, said hoses when inflated sealing the same against said stack. l

8. The apparatus of claim 6, wherein said stack is partly inserted into said first recited container, and further including horizontally and vertically slidable wall portions sealing said stack when so inserted into said first container, a resilient sealing strip carried at the inner end of said wall portions for resiliently engaging and sealing said stack, said wall portions comprising generally U-shape telescoping sections and inflatable hoses arranged between said sections, and valve means for inflating said hoses thereby forcing said resilient seal-ing strip against said stack in sealing relation thereto.

9. The apparatus of claim 6, wherein said stack of said panels is partly inserted into said first container, and further including a resilient sleeve surrounding said stack, the outer margin of said sleeve being clamped to the front wall of said first container, presser bars pressed on the inner margin of said resilient sleeve, and

inflatable hoses interposed between said sleeve and said bars for biasing said resilient sleeve into sealing 10. The apparatus of claim 6,-wherein said stack is positioned entirely within said first container, and further including a U-shaped frame straddling said stack 7 within said first container, pressure cylinders mounted on said frame for pressing against said stack, electrically insulating casings having contact brushes and seals between their edges and said stack, and further pressure cylinders mounted laterally on said frame pressing said casings and contact brushes against said stack, whereby upon the application of current said edges are electroplated.

11. The apparatus of claim 10, comprising horizontal guide rails supported on a wall of said first. container, vertical support means slidable in said guide rails, said further pressure cylinders, casings and contact brushes being mounted on said vertical supports. 12. The apparatus of claim 6, wherein said first 0on tainer is dismountable for separately receivingthe stackvof sheet metal panels, and further including a piling plate for said stack of sheet metal panels, a sealing frame on said piling plate, said first container having side walls ins'ertable in said sealing frame, inflatable hoses sealing said frame against said piling'plate and against said side walls, and-attachment means holding said side walls on said piling plate.

13. The apparatus of claim 12, wherein said attachment means comprise pivotable clamps articulated to said piling plate. 

1. Apparatus for electroplating the cut edges of sheet metal panels comprising: a. a container for the electrolyte, a lid for the container, and means for retaining said lid air tight on said container; b. means separate from said container for supporting a stack of said sheet metal panels and substantially aligning the edge portions of said panels on at least one side thereof; c. at least one anode mounted in said container; d. means for directly electrically contacting each sheet metal panel for connecting the same to the cathode of a direct current source, and e. means for conducting current to said contacting means whereby said cut edges are electroplated.
 2. The apparatus of claim 1, wherein said stack supporting means comprises holder plates covering said stack and having lateral projections, and abutment rods and contact bars mounted on said projections, said contact bars comprising said current conducting means.
 3. The apparatus of claim 1 wherein said container has an absorbent wall composed of members of permeable material, wire grids supporting said permeable members, a frame attaching said absorbent wall zone to said container, and sealing means interposed between said absorbent wall zone and said container.
 4. The apparatus of claim 3, further including strips of absorbent material clamped to said frame and having cross sections complementary to recesses in said cut edges of said panels.
 5. The apparatus of claim 3, further including a suction pipe communicating with the interior of said container, a collection trough for electrolyte dripping off said absorbent wall, an electrolyte return pipe, and a float valve arranged above the Electrolyte level in said container for controlling said return pipe.
 6. The apparatus of claim 1 further including a second container separate from said first container for storing the electrolyte, a pipe having a stop valve connecting said second container to said first recited container, and a pipe connecting said storage container to suction for filling the same with electrolyte and to pressure for emptying the same.
 7. The apparatus of claim 6, wherein said stack is partly inserted into said first recited container, and further including horizontally and vertically slidable wall portions sealing said stack when so inserted into said first recited container, rails mounted on said first container guiding said slidable wall portions, inflatable hoses and sealing strips provided on the end of faces of said movable wall portions, pressure cylinders having piston rods mounted on said first container and in operation pressing said wall portions on said stack, generally U-shaped frame sections arranged parallel to the edges of said wall portions, and inflatable hoses arranged in said sections, said hoses when inflated sealing the same against said stack.
 8. The apparatus of claim 6, wherein said stack is partly inserted into said first recited container, and further including horizontally and vertically slidable wall portions sealing said stack when so inserted into said first container, a resilient sealing strip carried at the inner end of said wall portions for resiliently engaging and sealing said stack, said wall portions comprising generally U-shape telescoping sections and inflatable hoses arranged between said sections, and valve means for inflating said hoses thereby forcing said resilient sealing strip against said stack in sealing relation thereto.
 9. The apparatus of claim 6, wherein said stack of said panels is partly inserted into said first container, and further including a resilient sleeve surrounding said stack, the outer margin of said sleeve being clamped to the front wall of said first container, presser bars pressed on the inner margin of said resilient sleeve, and inflatable hoses interposed between said sleeve and said bars for biasing said resilient sleeve into sealing engagement with said stack.
 10. The apparatus of claim 6, wherein said stack is positioned entirely within said first container, and further including a U-shaped frame straddling said stack within said first container, pressure cylinders mounted on said frame for pressing against said stack, electrically insulating casings having contact brushes and seals between their edges and said stack, and further pressure cylinders mounted laterally on said frame pressing said casings and contact brushes against said stack, whereby upon the application of current said edges are electroplated.
 11. The apparatus of claim 10, comprising horizontal guide rails supported on a wall of said first container, vertical support means slidable in said guide rails, said further pressure cylinders, casings and contact brushes being mounted on said vertical supports.
 12. The apparatus of claim 6, wherein said first container is dismountable for separately receiving the stack of sheet metal panels, and further including a piling plate for said stack of sheet metal panels, a sealing frame on said piling plate, said first container having side walls insertable in said sealing frame, inflatable hoses sealing said frame against said piling plate and against said side walls, and attachment means holding said side walls on said piling plate.
 13. The apparatus of claim 12, wherein said attachment means comprise pivotable clamps articulated to said piling plate. 